Device for increasing the heat output and energy storage in a heat pump

ABSTRACT

A device for controlling the heat output of a heat pump, with a storage circuit, wherein heat energy can be stored in a storage container, comprises means for receiving a volume flow of a heat carrier medium from a condenser of the heat pump and means in the circuit of the heat carrier medium for controllably feeding a volume flow of the heat carrier medium from a condenser of the heat pump to a desuperheater. In an embodiment of the invention, the device further comprises means in the refrigeration circuit of the heat pump for feeding the heat carrier medium from the desuperheater to the condenser of the heat pump.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is the national phase of PCT/DE2006//002002, filed Nov. 15, 2006 which is based on German Patent Application No. 102005055512.8, filed Nov. 17, 2005 and German Patent Application No. 102006052166.8, filed Nov. 2, 2006.

FIELD OF THE INVENTION

The present invention relates generally to a device for controlling the heat output of a heat pump with storage of heat energy.

BACKGROUND OF THE INVENTION

Heat pumps are used in heating and ventilation technology and for heat recovery. A heat carrier (water, brine, etc.) is frequently used for transferring the heat energy. The heat carrier flows through a condenser of a heat pump and there absorbs the energy of the heat pump. The heat carrier, in turn, transports the energy to the load and transfers the energy to the load; in this way, the heat carrier is cooled and then transported back to the heat pump and heated again in the condenser. To circulate the heat carrier a hydraulic module made from a circulating pump, pipes, shut-off valves, control fittings, manometer, and thermometer is generally used.

In refrigeration technology, so-called desuperheaters are known for heat recovery in the generation of cold air. With a desuperheater, the energy from the refrigeration circuit is removed from the flow of hot gas of a refrigeration circuit directly after the compressor of the refrigeration engine. With the hot gas, a higher water temperature can be generated than with the condenser. This is important for heating service water.

Various heat pumps have been described in the literature. A distinction should be observed between water/water heat pumps, brine/water heat pumps, and air/water heat pumps, as the energy is supplied by various heat sources in the various cases. Here, different hydraulic systems are employed. Those of skill in the art will be familiar with such systems and their usage. Generally, a container is used for increasing volume. This influences the cycle frequency of the compressor, stores energy, and regulates the heat output to the load. For economical and ecological reasons, two-condition operation with heat pump and boiler is also employed.

In the publication “Recknagel, Sprenger, Schramek, Handbook for Heating and Air-conditioning Technology 01/02, 2001 edition, Oldenbourg Industrieverlag Munich” on pages 569ff, various technologies for the heat carrier circuit are described. In the publication DE 10 2004 040 737 A1, a device for regulating a constant supply temperature is described. From the described state of the art, the highest heat carrier temperature is produced at the outlet of the heat carrier after the condenser.

The problem addressed by the invention is to raise the temperature level of the heat carrier and to store the maximum possible energy quantity in the storage container. Here it must be taken into account that the energy content of the refrigerant cannot change at a certain condensation temperature. However, if a higher temperature level of the heat carrier is reached, then for reaching the desired heat carrier temperature, the condensation temperature can be lowered, with the result that the electrical power consumption of the compressor is reduced and the output rating of the compressor is improved. Likewise, with the higher temperature level, more energy can be stored in the storage device, which reduces the cycle frequency of the compressor and thus the service life of the compressor.

OBJECTS AND SUMMARY OF THE INVENTION

The solution to the problem of raising the heat carrier temperature is implemented in a device for controlling the heat output of a heat pump, with a storage circuit, wherein heat energy can be stored in a storage container, the device comprising means for receiving a volume flow of a heat carrier medium from a condenser of the heat pump as well as means in the circuit of the heat carrier medium for controllably feeding a volume flow of the heat carrier medium from a condenser of the heat pump to a desuperheater. The solution to the problem of storing energy at a constant heat carrier supply temperature is implemented in such a device further comprising means in the refrigeration circuit of the heat pump for feeding the heat carrier medium from the desuperheater to the condenser of the heat pump.

The device contains a hydraulic circuit with storage device for raising the heat carrier temperature. Likewise, with this circuit the storage of energy can be performed at a higher temperature level in partial-load operation, at a constant or corrected supply temperature.

The invention is realized in a hydraulic system, which connects, in series or in parallel, a storage device, a circulating pump, pipes, necessary fittings for air ventilation and exhaust, fittings for regulation and also for guaranteeing operating reliability, temperature and/or pressure sensors, and also at least one desuperheater and/or a condenser.

The storage device is here constructed advantageously as stratified storage in such a way that hot heat carrier is removed at its top side and is also introduced again from above and that cold heat carrier is removed from its bottom side and also introduced again from below.

Through the interaction of the named components, it is possible to improve the output rating of the compressor/compressors for comparable heat carrier supply temperature, to keep the supply temperature of the heat carrier constant and to store a higher heat carrier temperature than the heat carrier supply temperature in the storage container in partial-load operation. With this invention, a heat pump can also be operated at the low temperature level, without falling below the limits of use of the compressor.

In a preferred embodiment, the series connection of the condenser and the desuperheater is selected for raising the heat carrier temperature. With the optional three-way valves, the full heat output of the heat pump is guided with the heat carrier directly to the load or for an excess of heat output, the warmer heat carrier is guided into the storage container. With another optional three-way valve, the load can be prevented from drawing too much energy from the heat carrier so that the condensation temperature does not drop so much that conditions fall below the limits of use of the compressor.

The advantages that can be achieved with the invention consist, among other things, of the following advantages:

1. An improvement of the output rating of the heat pump is achieved.

2. In the storage container, a heat carrier is stored at a higher temperature than is required for the heat carrier supply temperature at the load.

3. More energy can be stored in the storage container.

4. A smaller storage container can be selected.

5. The storage container is constructed as stratified storage, i.e., warmer heat carrier is removed at the top and also introduced from the top and cold heat carrier is removed at the bottom and also introduced from the bottom.

6. It is guaranteed that conditions do not fall below the limits of use of the compressor.

7. The invention can be used with a decentralized arrangement or integrated in a heat pump housing.

8. The heat carrier supply temperature can be corrected.

9. The energy output can be limited.

10. A boiler or other heat generator can be integrated in the hydraulic system.

11. The operating costs for the heat pump are minimized.

12. The service life of the heat pump is lengthened.

13. The CO₂ emissions are reduced.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

The invention will be described in more detail below using examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a first embodiment of the device according to the invention;

FIG. 2 illustrates a second embodiment of the device according to the invention;

FIG. 3 illustrates a third embodiment of the device according to the invention;

FIG. 4 illustrates a fourth embodiment of the device according to the invention;

FIG. 5 illustrates a fifth embodiment of the device according to the invention;

FIG. 6 illustrates a sixth embodiment of the device according to the invention;

FIG. 7 illustrates a seventh embodiment of the device according to the invention;

FIG. 8 illustrates an eighth embodiment of the device according to the invention;

FIG. 9 is a diagram of the temperatures of a water-water heat pump;

FIG. 10 ff are diagrams of the hydraulic system and a refrigeration circuit of a heat pump with reversing circuit for the refrigeration operation and defrosting circuit; and

FIG. 11 ff illustrate a water-water heat pump with stratified storage on the cold and the hot fluid sides of the heat pump.

While the invention is susceptible of various modifications and alternative constructions, a certain illustrative embodiment thereof has been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The device according to the invention is realized in a series circuit of a desuperheater 8 and a condenser (heat exchanger) 6 in a storage circuit and the regulating control valves 3, 5, 7, 17 according to FIG. 1.

A heat carrier circuit for heat transport between a heat pump and a load is coupled, on one side, by means of a condenser (heat exchanger) 6 and a desuperheater 8 of the heat pump and, on the other side, by means of a heat exchanger 4 via the pipe system to the load circuit. By means of a circulating pump 1, the heat carrier is circulated in the storage circuit. The heat carrier first flows through the condenser (heat exchanger) 6 and then a portion flows through the desuperheater 8. With a three-way valve 7, the portion for re-heating is controlled by the desuperheater 8. In the desuperheater 8, the heat carrier is reheated and fed to a pipe 9. For the three-way valve 7, as an economical solution, a throughput-controllable circulating pump with a conveying effect in the direction of the desuperheater 8 can also be used to simplify the structure. Furthermore, other control valves or throttling and distributing elements can also be used.

The working agent (refrigerant) first flows through the desuperheater 8 and then the condenser (heat exchanger) 6. The heat output of the heat pump thus can be brought to a higher temperature level after the condenser (heat exchanger) 6, because in the desuperheater 8, the working agent is still gaseous and also remains gaseous. Accordingly, it can also be cooled from a higher temperature level. Thus, in the desuperheater 8 the work of the condensation and supercooling of the refrigerant. Thus, it works at an already lowered temperature level. This benefits the loading of the heat pump.

With a three-way valve 17, the volume flows of the heat carrier from the condenser (heat exchanger) 6 and from the desuperheater 8 are recombined by means of a pipe 18 and fed via pipes 12 and 10 to the load.

In partial-load operation, a maximum possible volume flow portion is led with the three-way valve 17 into a storage container (buffer storage) 2. The heat carrier introduced into the storage container (buffer storage) 2 leaves this container via pipes 14 or 11, according to whether the storage container (buffer storage) 2 is filled with cold or hot heat carrier. If the storage container (buffer storage) 2 is filled with a hotter heat carrier than is required for the heat carrier supply temperature on the load, then the compressor switches off; for multiple-stage heat pumps, a compressor switches off.

If the heat carrier is not heated sufficiently by the heat pump, it is led via a three-way valve 3 proportionally through the storage container (buffer storage) 2, forces hot heat carrier out of the storage container (buffer storage) 2 and reaches the load via the pipe 14 and the three-way valve 3. If the heat carrier in the storage container (buffer storage) 2 is not sufficiently hot, a compressor switches back on. Excess energy that is possibly generated is fed via a pipe 9 and the three-way valve 17 back into the storage container (buffer storage) 2 and stored there. In the described operation, the storage container (buffer storage) 2 is used as stratified storage, that is, to the storage container (buffer storage) 2 either hot heat carrier is fed to its top side and colder heat carrier is removed from its bottom side or cold heat carrier is fed to the bottom side, while hot heat carrier is simultaneously removed at the top side.

The supply temperature required by the load is regulated with the three-way valve 3. An optional three-way valve 5 is used by means of a pipe 16 for limiting the energy reduction at the load. Thus, the heat carrier that is too cold is prevented from returning from the load, which would lower the condensation temperature in the condenser (heat exchanger) 6 so much that the compressor would operate outside of the operating limits.

In FIG. 2, the variant of the storage system according to FIG. 1 is shown without the pipe 16 and the three-way valve 5. In this way, the storage system is simplified.

In FIG. 3, the variant of the storage system according to FIG. 2 is shown without the pipe 18 and three-way valve 17. Thus, the storage system can be further simplified. Here, in this case only the control variant for the partial-load operation of the storage system for determining the maximum possible volume flow portion, which is to be guided in the storage container (buffer storage) 2, is eliminated. This embodiment can be completely sufficient, just like that according to FIG. 2, for wide regions of the operation of the system.

In FIG. 4, in an embodiment according to FIG. 3, as an optional equipment possibility for the system, a so-called reheater is shown, e.g., in the form of a boiler or an electric heater for supplying the load. The reheater can reheat or independently heat the heat carrier by means of a wide variety of known heating systems. Here, the heat exchanger 4 for connection of the load can be provided according to FIGS. 1 to 3 after the reheater. In this way, a two-condition operation of the heat pump is achieved. Furthermore, the reheater can be arranged in the storage circuit before the inlet of the heat carrier into the storage container (buffer storage) 2.

Similarly to FIG. 4, according to the embodiment according to FIG. 5, the load can be coupled instead of via a heat exchanger 4 also directly to the heat carrier circuit or storage circuit. Furthermore, the three-way control valve 7 used before has been replaced in an alternative embodiment with two more economical manual control valves 19 in the pipes 12 and 13.

FIG. 6 shows a possible arrangement of the combination of a desuperheater 8 and a condenser (heat exchanger) 6 in a parallel circuit. For such an arrangement in a parallel circuit, obviously all of the combinations of the system from FIGS. 1 to 5 can also be selected. However, in terms of energy, the arrangement is not as effective as the series circuit of the condenser (heat exchanger) 6 and desuperheater 8.

FIG. 7 contains a possible arrangement according to FIG. 3 with a condenser (heat exchanger) 6 and without a desuperheater 8. Here, the energy storage in the storage container (buffer storage) 2 is used for increasing the efficiency of the heat pump. The use of the storage container (buffer storage) 2 as stratified storage increases the efficiency of the storage circuit.

FIG. 8 contains a possible arrangement of the combination of condenser (heat exchanger) 6 and desuperheater 8 without a storage circuit with buffer storage. This variant can be operated such that the water temperature can be raised, in order to lower the condensation temperature of the working agent or to keep it low. In this way, the heat pump is used more efficiently. The heat carrier circuit here is the cooling water circuit of the refrigeration engine. Storage of the energy can be realized advantageously on the evaporator side of the heat pump.

FIG. 9 shows a diagram of temperatures, which can be set in a hydraulic module and refrigeration circuit. The arrangement essentially corresponds to that of FIGS. 3 to 5. Essentially, the mentioned arrangement is expanded by elements of the heat pump that have not yet been described. A heat exchanger 19 for absorbing energy from a fluid, which is supplied by a pump 1.2 in a secondary circuit, is coupled to a compressor 20. The liquid-gas line, which leads from the heat exchanger 19 to the condenser (heat exchanger) 6 of the heat pump, is a collector 21, a filter drying group 22, and an expansion valve 23 for treating the condensed working agent (refrigerant). On the load side, in the circuit of the heat carrier, there is disposed a heat exchanger 24 for generating hot pump water PWW. The heat exchanger 24 carries a flow of heat carrier by means of pump 1.3. At the appropriate transfer points of the circuits, the set working temperatures are recorded as examples.

FIGS. 10.1 to 10.4 each show an air-water heat pump with a reversible refrigeration circuit for a thawing circuit. Care is taken that the active sense of the heat exchanger is not reversed in the air flow (equal flow or counter flow).

FIG. 10.1 shows an air-water heat pump with an optional heat exchanger connected downstream, with which energy (PWW) can be transferred into or out of the system. The heat exchanger 24 is provided on the load side.

On the side of the heat pump, a heat exchanger 33 is provided, which can be integrated into the energy circuit by means of a compressed-gas line 29 and automatic valves 26, so that an optional guidance of the working agent (refrigerant) directly to the desuperheater 8 or to the heat exchanger 33 is possible. The energy transport from the heat exchanger 33 is guided via an expansion valve 23 and a fluid line 31 to the already described treatment stations 21, 22 of the working agent (refrigerant).

The connection of the compressor 20 to the condenser (heat exchanger) 6 is guided via an automatic valve 26, a suction pressure line 30, and a non-return device 25. Furthermore, here a fluid separator 27 is provided. Furthermore, by means of a suction gas/fluid line 32 switchable by means of a valve 26 and protected, is created the condenser (heat exchanger) 6.

FIG. 10.2 shows the air-water heat pump according to FIG. 10.1 but with a hydraulic changeover of the heat carrier, thus, the condenser (heat exchanger) 6 operates exclusively according to the counter-flow principle. Here, a four-way valve 28 is provided in the connection of the condenser (heat exchanger) 6 to the storage circuit, so that the flow direction can be adjusted to sides of the storage circuit according to the effective direction of the heat pump circuit.

FIG. 10.3 shows an air-water heat pump according to FIG. 10.1 with a heat exchanger 34, which is also connected in parallel to the heat exchanger 33, for distributing the condensation heat. With another heat exchanger 50, an additional heat source can be used for the heat pump operation.

FIG. 10.4 shows a reversible air-water heat pump according to FIG. 10.1 for the heating and cooling operation with air dehumidification using the example of a ventilation device. For the cooling case of the supply air, the heat exchangers 33 and 34 are used as condensers. For increasing the condensation capacity, an adiabatic humidifier can be used before the heat exchanger 33. For further increasing capacity, an adiabatic cooler 36 can also be used before the heat exchanger 34. The condenser (heat exchanger) 6 is used as an evaporator and thus generates cold fluid. Valve 26.1 is closed, and the desuperheater is thus deactivated. With the heat exchanger 37, energy is removed from the refrigeration circuit and transported via the heat carrier with the circulating pump 41 to the heat exchanger 40. The heat transport can be fed in a controlled way via a three-way valve 51 to the heat exchanger 40 in a bypass connection.

FIG. 10.5 shows an air-water heat pump according to FIG. 10.1 in a simplified construction. Here, the connection between the heat pump circuit and the storage circuit is created exclusively via the heat exchanger (condenser) 6, i.e., there is no desuperheater.

FIG. 11.1 shows a water-water heat pump with energy storage on the cold and hot heat carrier sides. By means of a circulating pump 42, heat carrier is guided from a heat exchanger 50 via two three-way valves 43, 44 and pipes 45 to 49 to a storage container 51. Thus, by means of the three-way valves 43, 44, cold/hot heat carrier can be stored controlled in the circuit of the heat pump in the storage container 51, while simultaneously on the side of the storage circuit, conversely, hot/cold heat carrier can be disposed. Both storage containers (buffer storage) 2, 51 can also be operated as stratified storages.

FIG. 11.2 shows the arrangement according to FIG. 11.1 in a simple construction, wherein the heat transport between the storage circuit and the heat pump circuit is performed only by means of the condenser (heat exchanger) 6.

FIG. 11.3 shows a water-water heat pump with energy storage on the cold and hot heat carrier sides according to FIG. 11.1. Here, an external heat source is provided within a pipe 9 for the two-condition operation of the system. The external heat source can be constructed as an electric heater. Here, hot heat carrier is fed via the pipe 9 to the top side of the storage container (buffer storage) 2. The additional heat stored in this way can then be discharged, when necessary, to the load, also for recovery of hot pump water PWW. The desuperheater 8 here is coupled on the supply side directly to the load. The storage control of the heat carrier is then realized via the coupling point of the three-way valve 7.

FIG. 12 shows in the right area of the diagram an air-air heat pump with reversible refrigeration circuit in a comparable arrangement of the heat pump according to FIGS. 10.1 to 10.4. Here, however, on the side of the evaporator and the condenser, there are sheet heat exchangers 33. Also no storage containers are provided. Here, the active sense of the sheet heat exchangers 33 is always realized as counter-flow heat exchangers, wherein minimum fitting expense is necessary. Expansion valves 23 allocated to the heat exchangers 33 act like solenoid valves in the rest state. The reversal of the refrigeration circuit is realized by means of two control valves 26 in connection with a division of the pipe 29, which goes out from the compressor 20 and which leads to the heat exchangers 33. In this way, the working agent (refrigerant) can be guided selectively first via the left or the right sheet heat exchanger 33. By switching the return of the two heat exchangers 33 via a common return line with the expansion valves 23, the heat exchangers 33 always work according to the counter-flow principle desired for optimized heat transfer.

In all of the embodiments, a distribution of the heat carrier volume flows with manual fittings is possible instead of with valves that are adjustable by motors. Motor drives can also be replaced by magnetic drives.

LIST OF REFERENCE SYMBOLS

-   -   Circulating pump 1     -   Storage container 2     -   Three-way valve 3     -   Heat exchanger 4     -   Three-way valve 5     -   Desuperheater 6     -   Three-way valve 7     -   Condenser 8     -   Pipe 9 to 16     -   Three-way valve 17     -   Pipe 18     -   Heat exchanger 19     -   Compressor 20     -   Collector 21     -   Filter drying group 22     -   Expansion valve 23     -   Heat exchanger 24     -   Non-return flow device 25     -   Automatic valve 26     -   Flow separator 27     -   Four-way valve 28     -   Compressed gas line 29     -   Suction pressure line 30     -   Fluid line 31     -   Suction gas/fluid line 32     -   Heat exchanger 33, 34     -   Pipe 35     -   Heat exchanger 36, 37     -   Three-way valve 38, 39     -   Heat exchanger 40     -   Circulating pump 41, 42     -   Three-way valve 43, 44     -   Pipe 45 to 49     -   Heat exchanger 50     -   Three-way valve 51 

1-24. (canceled)
 25. A device for controlling the heat output of a heat pump, with a storage circuit, wherein heat energy can be stored in a storage container, the device comprising: means for receiving a volume flow of a heat carrier medium from a condenser of the heat pump; and means in the circuit of the heat carrier medium for controllably feeding a volume flow of the heat carrier medium from a condenser of the heat pump to a desuperheater.
 26. The device according to claim 25, further comprising means in the refrigeration circuit of the heat pump for feeding the heat carrier medium from the desuperheater to the condenser of the heat pump.
 27. The device according to claim 25, wherein the condenser and the desuperheater are connected in series in the circuit of the heat carrier medium.
 28. The device according to claim 25, wherein the condenser and the desuperheater are connected in parallel in the circuit of the heat carrier medium.
 29. The device according to claim 25, wherein the volume flow of the heat carrier medium from the condenser to the desuperheater is controllable, wherein at least a partial volume flow can be fed by means of pipes via a control or conveyor device to the desuperheater and then to a storage circuit and the other partial volume flow can be fed via pipes directly to the load and/or likewise to the storage circuit.
 30. The device according to claim 25, wherein the condenser and desuperheater can be switched separately in order to be able to operate the condenser and the evaporator.
 31. The device according to claim 25, wherein one of the condenser, the heat pump and the desuperheater are mounted outside of the storage container.
 32. The device according to claim 25, wherein the refrigeration circuit is configured with only one condenser.
 33. The device according to claim 25, wherein the refrigeration circuit is configured with a reversible condenser/evaporator.
 34. The device according to claim 25, wherein in the heat carrier circuit, another heat exchanger is integrated, in order to achieve hydraulic separation between two heat carriers, wherein, as the second heat carrier, service water heating is also to be applied.
 35. The device according to claim 25, wherein, in the heat carrier circuit, one or additional heat exchangers is/are integrated, in order to achieve hydraulic separation between several heat carriers, wherein, as the additional heat carrier, service water heating or a heat carrier from a boiler is to be applied for the two-condition operation.
 36. The device according to claim 25, wherein several hydraulic modules are connected in parallel.
 37. The device according to claim 25, wherein one or more pumps are connected in parallel.
 38. The device according to claim 25, wherein one or more pumps are connected in parallel in a rotational speed-controlled manner.
 39. The device according to claim 25, wherein the inlet and outlet from the storage container are provided with devices which are used for distributing the heat carrier in the storage container and pipe system.
 40. The device according to claim 25, wherein, in or outside of the storage container, devices are introduced for the division and flow direction of the heat carrier.
 41. The device according to claim 25, wherein the valves are placed at different positions in the pipe system, so that a mixing value becomes a distributing value or a distributing value becomes a mixing value.
 42. The device according to claim 25, wherein, in the storage circuit and/or in the heat pump circuit, there is one or more temperature sensors and/or flow-rate sensors for finer control of the system.
 43. The device according to claim 25, wherein, in each medium circuit for cold and hot heat carrier, there is a storage container.
 44. The device according to claim 25, wherein, for the condensation of the refrigerant and for the evaporation of the refrigerant, one or more heat exchangers are present in the same or a different configuration.
 45. The device according to claim 25, wherein the refrigeration circuit for the heat pumps includes an air-water heat pump with a reversible refrigeration circuit for a thawing circuit.
 46. The device according to claim 25, wherein the configuration of the refrigeration circuit for the heat pumps has no collector.
 47. The device according to claim 25, wherein the configuration of the refrigeration circuit for the heat pumps has no fluid separator.
 48. The device according to claim 25, wherein the configuration of the refrigeration circuit for the heat pumps is constructed as an air-air heat pump and that one or more devices are provided for switching the flow direction of the working medium, wherein each heat exchanger can be used as an evaporator or condenser. 